Method of making electrical condensers



Dec. 12, 1 950 P- R. COURSEY ETAL METHOD OF MAKING ELECTRICAL CONDENSERS INVENTOR 5 PAM/P Any Caweszv 2 Sheets-Sheet 1 I'll an OriginalFiled Dec; 27, 1946 i flu ATTORNEY Dec. 12, 1950 P. R. COURSEY. ETAL 3,7

METHOD OF MAKING ELECTRICAL CONDENSERS Original Filed Dec. 27, 1946 2 Sheets-Sheet 2 ATTORNEY Patented Dec. 12, 1950 METHOD OF MAKING ELECTRICAL CONDENSERS Philip Ray Coursey, Kingston, Charles Henry Munday, Barnes, and Kathleen Agnes Gough, Sutton, England, assignors to Engineering Development Laboratories, Inc., New York, N. Y., a corporation of New York Original application December 27, 1946, Serial No. 718,634, Divided and this application May 14, .1948, Serial No. 26,998. In Great Britain May 9 Claims. (Cl. 242-55) I This application is a division of Serial #718,634

porous materiaLthe rolled'unit 'being usually i 1 treated with a suitableimpregnant.

The invention has for its object to provide an improved condenser of this kind, and an improved-method of manufacture thereof, whereby a robust construction having ahigh ratio of electrostatic capacityto mechanical volume will be obtained. M

According to .the invention, the flexible elements are wound on asingle central conducting ,wire core which is held in tension whilst being rotated about its longitudinal axis, the drive being preferably applied to the wire core at both ends thereof simultaneously.

Conveniently, a first flexible, electrode element or foil is electrically connected to the wire core "which thus constitutes one of the condenser terminals. In a preferred method, thefirst flexible electrode element is electrically and mechanically connected to the wire core, the subsequent flexible elements being drawn in between the rotating core and the part of the first electrode element tangential thereto. The wire core may be tinned, that is to say precoated with tin or an alloy such as solder, and the first electrode element secured to the tinned wire by applying heat to the junction, as by means of a soldering iron,

without the application of additional solder. Al-

ternatively, the first flexible electrode may be attached to the wire core by a spot welding operation, or by the use of some other convenient adhesive.

. 2 Figure 2 illustrates the chucks and winding gear in section taken on line 2-'-2 of F g re 1;;

Figures 3 to 6 show, on an enlarged scale, the initial steps involved in connecting the first strip of foil and the first spacer strip to the core; I

Figure 7 is a detail view of one of the guide rollers shown in Figure 1; T

Figures 8 and 9 are views similar to Figures 5 and 6 and indicating the steps of connecting the second foil and paper strips to the core;

Figure 10 is -a view-similar to that of Figures 8 and 9 but on an enlarged scale and indicating the manner of insertion of a connecting tab for joining to one of the terminals;

Figure 11 shows the rolled or cartridge-like unit in side elevation; and

Figure 12 illustrates the unit arranged within a metal thimble which is shown in longitudinal section. 4

' Like reference numerals identify like parts throughout the different views of the drawings.

The above mentioned and further objects as apparatus in side elevation;

As'shown in Figure 1, a length of tinned copper wire In having an overall diameter of about 0.020 inch is threaded through the axial bores in two aligned rotary chucks H and i2, respectively, carried between supports l3 mounted on.-a base l4, one or each of the chucks having an axial micrometer adjustment [5 (Figure 2) whereby the wire can be subjected to a required degree-of mechanical tension after the wire has been gripped in the checks H and I2 by tightening the heads l6 and I1. Thetwo chucks ll and.l2. are driven in synchronism, through a handle l8 and toothed gearing 20, so that the drive is applied to both ends of the wire simultaneously. Carried by members 2| and 2 I on the base [4 with their axes parallel to the axis of rotation-of the-wire 10 are a plurality of supply rolls (Figure 1) two of which 22 and 23 are constituted by strips of metal foil whilst two others 24 and 25 are constituted by strips of paper which are to constitute the insulating spacers between the foils or electrodes. A third roll 26 carries a strip of wrap I ping paper, preferably a thin Kraft tissue, somewhat wider than the paper strips 24 and 25. The foils 22 and 23 may have a thickness of, say, not more than 5 microns whilst the paper spacers 24 and 25 may have a thickness. of up tov 12 microns if used single or up to 6.5 to 7.0 microns if used in pairs. Where single paper spacers are used, it issometimes found advantageous to. coat index mark 44 on the ramp 31. [carried on until the mark on the foil 23 reaches a. second index mark, which may conveniently be located, on the to of the guillotine frame 43, whereupon the guillotine 30 is operated to sever [the Strips 22 and 24. The paper strip 25is'then severed approximately in line with the cut end of 24. The disposition of the foil 22 and the one or both sides of them, but referably one side only, with a layer of lacquer or varnish for the purpose of filling up the irregularities in the paper surface which is adjacent to a metal electrode and so to reduce the liabilities to breakdown tin'eughthin portions of the tissue.

The end of the strip of foil 22 from the lowermost roll is laid between two horizontal steel rollers 2! and 28, the upper roller 2'2 being conveniently rubber covered and resting on the upper surface of the foil 22 by gravity alone. These two rollers 2i and 28 act not only to maintain the foil 22 accurately in a single plane but also serve as a, brake to hold the foil in slight tension and prevent its return movement towards the supply roll. As shown in Figure 3; the free end of this metal foil 22, having been threaded through a slot in a guillotine 30, is bent round the wire In extending between the chucks H and "and/"or so-lderin-g flux. The foil 22 is thus sold-- ered to the wire Ii] without risk of the formation of pimples or irregularities which might not only tend to pierce the paper spacer applied over 7 the foil but would cause irregularities of take-up of the flexible elements as they are wound 'on the wire core it. The end portion 3-2 of the foil 22 "having been torn ofi along the soldering line 3?;

in the counter-clockwise direction as viewed in Figure l so that the wire it acts as a mandrel a nd the foil 22, or first electrode element, laps the wire 15.

The end of the paper strip 24 (or paper strip 24 through the guillotine is such that this operation leaves the cut end of 22 protected by the slightly longer and projecting ends of the paper strips 24 and 25. Winding is now continued until the ends of 24, 25, and 22 approach the mandrel I 0, when. a short length of wrapping paper, preferably of kraft tissue, 45 from the roll 26 is inserted between the strips 25 and 23 as shown in Figure 10, this paper 45 projecting to the right. of the rolled unit as viewed in Figure 2. Following the paper strip 45 a metal tab 46 is insertedlying against the foil 23 and is wound in so that it: is gripped between the convolutions of the foil, the tab 46 projecting to the left of the rolled unitas viewed in Figure 2. Finally the remaining foil 23 is severed. The first strip of foil 22 has a width only slightly less than that of the paper spacers. 24 and 25 so that the paper lust protrudes (as shown in Figure 11) at each 7 end of the rolled unit as this proceeds to be built up. The second. strip of foil 23 is, however, appreciably narrower than the first so that whilst the paper spacers 24 and 25 give ample mutual separation at the edges. of the two foils or electrodes, the paperspacers and first foil 22 together ensure a rigid and robust construction for the rolled unit.

As will be apparent from Figure 10, the second g and narrower strip of foil 23 extends longitudias indicated in Figure 5, the handle is turned two such. strips) is, as shown in Figure 6, taken core i0 and. the, first foil 22 tangential thereto.

The handle 18 is now turned slightly so that the end of the paper strip 24 is wound in, whereupon the end of the second paper strip. 25 is laid over It will be understood that Having to wind in the end of the paper strip 25, the end of the foil 22 is laid over the strip 24 on the ramp 3 1 and thence over the frame 43 of the guillotine to the angle between the papers 24 and 25 as shown in Figure 9.

When the r011 23. is initially threaded in as shown in Figure 9 the requisite length to be wound ismarked on the foil with the as istance of an Winding is now irom'the paper supply roll and over'two idler or guide rollers and 35 interconnected by an inclined ramp 3? whose ends are laid on the hubs or the rollers as indicated in Figure 7, and is threaded through a slot 38 of the guillotine 35, "and thence to the angle formed between the wire naliy somewhat beyond the first foil 22 and, spacers. 24 and 25 so that when the rolled unit is completed the end portion of the second foil 23 is exposed at the exterior cylindrical surface of the unit as clearly shown in Figure 11. This central cylindrical exposed portion oi the second foil provides for one. terminal of the condenser, as described below. The end of the second foil 23 is now lightly secured against unrolling, say by a trace of adhesive material, and the rolled unit is removed from the chucks [I and I2.

As shown in Figure 12, the end of the core is included in Figure 11 is out 01f substantially flush with the adjacent end of the rolled-unit which is inserted into a tinned. metal thimble or pot 5E. The projecting fringe of the kraft paper presses against the base of the pot and is thus folded inwards towards the remaining core terminal 52 Having folded the terminal tag 46 over the end of the pot 5| and soldered, the tag to the. pot. an insulating washer 53, for example of mica, is. laid in. the open end of. the pot where.- upon a metal disc. 54. electrically and mechanical.- ly connected to a terminal lead 55 is inserted over the washer 53 and this terminal. assembly soldered in the mouth of the pot- 5! as: shown at 56.

The rolled unit, is preferably treated with a suitable irnpregnantv This, impregnant may be of any of the well known materials used with ordinary condensers such, for example, as mineral oils, jellies or waxes. Preferably, however. in order toobtain as large an electrostatic capacity as possible consistent with small dimensions, impregnants of high di-electric constants may be used, such, for example, as chlorinated naphthalenes, chlorinated diphenyls, or hydrogenated or hydroxylated products of castor oil, in accordance with well known practice.

' While there. has been shown and. described. in the foregoing a preferred embod ment of the invention, it is understood that this disclosure is for the purpose of illustration and that various changes in. shape, proportion and arrangement of parts, as well as the substitution of equivalent elements and materials-for those hereinv shown and described may be made without departing from the spirit and scope of the invention as defined in the appended claims. For example, when the rolled unit is arranged within a terminal thimble or sleeve, a plug, bushing or bushings of glass, ceramic or like material may be secured to the thimble or sleeve in a moisturetight manner as, for example, by soldering to a metallized coating or by the use of a sealing glaze or the like. The specification and drawings are, accordingly, to be regarded in an illustrative rather than a limiting sense.

We claim:

1. A method of manufacturing electrical condensers which comprises spirally winding a plurality of interleaved flexible conducting and insulating elements upon a rotating conducting wire core, while applying tension to said core during the winding operation.

2. A method of manufacturing electrical condensers comprising spirally winding a plurality of interleaved flexible conducting and insulating elements upon a central conducting'wire core rotatively driven at both ends thereof simultaneously, while applying tension to said core during the winding operation.

3. A method of manufacturing electrical condensers which comprises electrically and mechanically connecting the end of a first flexible electrode strip to a central conducting wire core, and winding said strip together with interleaved additional conducting and insulating strips into a rolled condenser unit by rotation of said core, while applying tension to said core during the winding operation.

4. A method of manufacturing electrical condensers which comprises electrically and mechanically connecting the end of a first electrode strip to a central conducting wire core, and winding said strip together with interleaved additional conducting and insulating strips into a rolled condenser unit by applying rotation to said core at both ends thereof simultaneously, while maintaining said core under tension during the winding operation.

5. A method of manufacturing electrical condensers comprising electrically and mechanically connecting the end of a first flexible electrode strip to a central conducing wire core, rotatively driving both ends of said core and causing additional electrode and insulating strips to be subsequently drawn between the rotating core and the part 6 of the first electrode tangential thereto to produce a rolled condenser unit, while maintaining said core under tension during the winding operation.

' 6. A method of manufacturing electrical condensers comprising placing the end of a first 'core and the part of said first strip tangential thereto to produce a rolled condenser unit, while maintaining said core under tension during the winding operation.

7. A method of manufacturing electrical condensers of the rolled type comprising spirally winding flexible insulating and conducting layers upon a rotating conducting wire core, and applying tension to said core during the winding operation.

8. A method of manufacturing electrical condensers of the rolled type comprising spirally winding insulating and conducting layers upon a conducting wire core rotatively driven at both ends simultaneously, and applying tension to said core during the winding operation.

9. A method of manufacturing electrical condensers of the rolled type comprising securing the end of a flexible condenser element to a conducing wire core, applying mechanical tension to said core, and rotating said core while under tension, for winding thereon alternate conducting and insulating layers, to produce a rolled condenser unit.

PHILIP RAY COURSEY. CHARLES HENRY MUNDAY. KATHLEEN AGNES GOUGH.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 728,780 Splitdorf May 19, 1903 1,744,616 Cunningham Jan. 21, 1930 1,960,944 Knudsen May 29, 1934 

